Solve these clues to fill the grid.
- Undesirable state of the natural environment being contaminated with harmful substances as
- 1 Across
- Whether it's rainy, sunny or windy outside
- 4 Across
- The prevailing psychological state
- 5 Across
- The branch of geology studying the folding and faulting of the earth's crust
- 8 Across
- Long stream of water flowing to the sea (plural)
- 9 Across
- A system formed by the interaction of a community of organisms with their physical environment (plural)
- 10 Across
- The organized action of making of goods and services for sale
- 11 Across
- A mathematical relation such that each element of a given set is associated with an element
- 12 Across
- The number of inhabitants in a given place
- 1 Down
- A process in which something passes by degrees to a different stage
- 2 Down
- Buying things at stores
- 3 Down
- The maintenance of a certain quantities unchanged during chemical reactions or physical
- 5 Down
- The business of providing services to ___
- 6 Down
- A body of people who ___ far from home but maintain ties with their homeland
- 7 Down